meteorimpact

Meteor impact refers to the collision of a meteoroid with a planetary surface, most often Earth. Most small meteoroids burn up in the atmosphere, but larger bodies can survive to release energy upon impact and form a crater. The final feature’s size depends on the object’s mass, velocity, entry angle, and the target’s properties, ranging from simple bowls to large basins.

Impact dynamics begin with atmospheric entry, during which the body heats, ablates, and fragments. If a substantial object reaches the surface, it releases a high-energy plume that excavates a transient crater. This crater then relaxes through modification into the final form, often with a raised rim, terraced walls, a central peak, and an ejecta blanket. Small, bowl-shaped craters are classed as simple; larger ones are complex.

Earth preserves many impact structures and, in concert with lunar and planetary craters, informs solar system history. Notable terrestrial examples include Barringer Meteor Crater in Arizona, Chicxulub off Mexico’s Yucatán Peninsula (linked to the Cretaceous–Paleogene extinction), Sudbury Basin in Ontario, Vredefort Dome in South Africa, and Popigai in Siberia. Evidence includes shocked minerals, elevated iridium layers, and ejecta patterns that help reconstruct events.

Hazards range from rare, global-scale impacts to more frequent, localized effects from smaller fragments. Near-Earth-object programs catalog and monitor potentially hazardous bodies and study deflection strategies, such as kinetic impactors. Cratering research also informs planetary defense planning and the interpretation of planetary surfaces, contributing to our understanding of Earth's history and the dynamics of the solar system.